Journal articles on the topic 'Rockfal hazard'
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1
Hartmeyer, Ingo, Markus Keuschnig, Robert Delleske, Michael Krautblatter, Andreas Lang, Lothar Schrott, Günther Prasicek, and Jan-Christoph Otto. "A 6-year lidar survey reveals enhanced rockwall retreat and modified rockfall magnitudes/frequencies in deglaciating cirques." Earth Surface Dynamics 8, no. 3 (September 11, 2020): 753–68. http://dx.doi.org/10.5194/esurf-8-753-2020.
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Abstract. Cirque erosion contributes significantly to mountain denudation and is a key element of glaciated mountain topography. Despite long-standing efforts, rates of rockwall retreat and the proportional contributions of low-, mid- and high-magnitude rockfalls have remained poorly constrained. Here, a unique, terrestrial-lidar-derived rockfall inventory (2011–2017) of two glaciated cirques in the Hohe Tauern range, Central Alps, Austria, is analysed. The mean cirque wall retreat rate of 1.9 mm a−1 ranks in the top range of reported values and is mainly driven by enhanced rockfall from the lowermost, freshly deglaciated rockwall sections. Retreat rates are significantly elevated over decades subsequent to glacier downwasting. Elongated cirque morphology and recorded cirque wall retreat rates indicate headward erosion is clearly outpacing lateral erosion, most likely due to the cataclinal backwalls, which are prone to large dip-slope failures. The rockfall magnitude–frequency distribution – the first such distribution derived for deglaciating cirques – follows a distinct negative power law over 4 orders of magnitude. Magnitude–frequency distributions in glacier-proximal and glacier-distal rockwall sections differ significantly due to an increased occurrence of large rockfalls in recently deglaciated areas. In this paper, the second of two companion pieces, we show how recent climate warming shapes glacial landforms, controls spatiotemporal rockfall variation in glacial environments and indicates a transient signal with decadal-scale exhaustion of rockfall activity immediately following deglaciation crucial for future hazard assessments.
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Birien, Tom, and Francis Gauthier. "Assessing the relationship between weather conditions and rockfall using terrestrial laser scanning to improve risk management." Natural Hazards and Earth System Sciences 23, no. 1 (January 27, 2023): 343–60. http://dx.doi.org/10.5194/nhess-23-343-2023.
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Abstract. Since 1987, more than 13 200 rockfalls have been inventoried by the ministère des Transports du Québec (MTQ) as having impacted the national road Route 132 in northern Gaspésie. This natural hazard represents a nearly permanent danger for road users. Traditional mitigation measures can be ineffective on poorly consolidated, deformed and highly fractured rockwalls such as those found in northern Gaspésie. To address this issue, implementing preventive risk management based on the factors that trigger rock instabilities could be the most effective method. Earthquake, rainfall and freeze–thaw cycles are commonly considered to be the main rockfall-triggering factors. This study aims to better understand the climatic conditions conducive to rockfalls in northern Gaspésie in order to provide knowledge to implement an appropriate risk management strategy. Three rockwalls were scanned with terrestrial laser scanning (TLS) instruments during specific pre-targeted weather conditions. Over a period of 18 months, 17 surveys have allowed us to identify 1287 rockfalls with a magnitude above 0.005 m3 on a scanned surface of 12 056 m2. In addition, meteorological instruments and a 550 cm thermistor string have been installed directly on a vertical rockwall. It appears that some weather conditions influence the occurrence, frequency and magnitude of rockfalls. In winter, rockfall frequency is 12 times higher during a superficial thaw than during a cold period in which temperature remains below 0 ∘C. In summer, rockfall frequency is 22 times higher during a heavy rainfall event than during a mainly dry period. Superficial freeze–thaw cycles (< 50 cm) cause mostly a high frequency of small-magnitude events, while deeper spring thaw (> 100 cm) results in a high frequency of large-magnitude events. The influence of weather conditions on rockfall frequency and magnitude is crucial in order to improve risk management, since large-magnitude events represent higher potential hazards. This study provides a classification of weather conditions based on their ability to trigger rockfalls of different magnitudes. This knowledge could be used to implement a risk management strategy.
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Kanari, Mor, Oded Katz, Ram Weinberger, Naomi Porat, and Shmuel Marco. "Evaluating earthquake-induced rockfall hazard near the Dead Sea Transform." Natural Hazards and Earth System Sciences 19, no. 4 (April 18, 2019): 889–906. http://dx.doi.org/10.5194/nhess-19-889-2019.
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Abstract. We address an approach for rockfall hazard evaluation where the study area resides below a cliff in an a priori exposure to rockfall hazard, but no historical documentation of rockfall events is available and hence important rockfall hazard parameters like triggering mechanism and recurrence interval are unknown. We study the rockfall hazard for the town of Qiryat Shemona, northern Israel, situated alongside the Dead Sea Transform, at the foot of the Ramim escarpment. Numerous boulders are scattered on the slopes above the town, while pre-town historical aerial photos reveal that boulders had reached the location that is now within town limits. We use field observations and optically stimulated luminescence dating of past rockfall events combined with computer modeling to evaluate the rockfall hazard. For the analysis, we first mapped the rockfall source and final downslope stop sites and compiled the boulder size distribution. We then simulated the possible rockfall trajectories using the field observed data to calibrate the simulation software by comparing simulated and mapped boulder stop sites along selected slopes, while adjusting model input parameters for best fit. The analysis reveals areas of high rockfall hazard at the southwestern quarters of the town and also indicates that in the studied slopes falling blocks would stop where the slope angle decreases below 5–10∘. Age determination suggests that the rockfalls were triggered by large (M>6) historical earthquakes. Nevertheless, not all large historical earthquakes triggered rockfalls. Considering the size distribution of the past rockfalls in the study area and the recurrence time of large earthquakes in the region, we estimate a probability of less than 5 % to be affected by a destructive rockfall within a 50-year time window. Here we suggest a comprehensive method to evaluate rockfall hazard where only past rockfall evidence exists in the field. We show the importance of integrating spatial and temporal field observations to assess the extent of rockfall hazard, the potential block size distribution and the rockfall recurrence interval.
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Colangelo, G., and A. Guariglia. "A Combined Methodology for Landslide Risk Mitigation in Basilicata Region by Using LIDAR Technique and Rockfall Simulation." International Journal of Geophysics 2011 (2011): 1–5. http://dx.doi.org/10.1155/2011/392676.
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Rockfalls represent a significant geohazards along the SS18 road of Basilicata Region, Italy. The management of these rockfall hazards and the mitigation of the risk require innovative approaches and technologies. This paper discusses a hazard assessment strategy and risk mitigation for rockfalls in a section of SS118, along the coast of Maratea, using LIDAR technique and spatial modelling. Historical rockfall records were used to calibrate the physical characteristics of the rockfall processes. The results of the simulations were used to define the intervention actions and engineering strategy for the mitigation of the phenomena. Within two months, 260 linear meters of high-energy rockfall barriers for impact energies up to 3000 kJ were installed. After that, according to road authority, the SS18 road was opened in a safe condition. The results represent a valid cognitive support to choose the most appropriate technical solution for topography strengthening and an example of good practice for the cooperation between innovative technologies and field emergency management.
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Saroglou, H. "Rockfall hazard in Greece." Bulletin of the Geological Society of Greece 47, no. 3 (December 21, 2016): 1429. http://dx.doi.org/10.12681/bgsg.10982.
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The geological structure of Greece (frequent occurrence of rock formations, existence of faults and fracturing of rocks), the steep topography and mountainous terrain as well as its high seismicity, creates a significant rockfall hazard. During the last decades, rockfalls in Greece are becoming a frequent phenomenon due to the increase of intense rainfall events but also due to the extension of human activities in mountainous areas. The paper presents rockfall hazard in Greece trough an inventory of rockfalls and investigates the correlation of specific factors, namely: a) triggering mechanism (rainfall, seismicity), b) slope angle, c) lithology, d) fault presence, e) block size in the probability of occurrence of these, based on a statistical approach. The time and space frequency of the events is also investigated. Finally, the impact of the events on human and infrastructures (transportation infrastructure, inhabited areas, archaeological sites) is discussed.
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Macciotta, Renato, Frank Altamirano, Lachlan Gibbins, Marco Espezua, Rubén Fernández, and Javier Maguiña. "Rock Fall Hazard Analysis for In-Pit Operations Potentially Impacting External Sensitive Areas." Mining 1, no. 2 (June 23, 2021): 135–54. http://dx.doi.org/10.3390/mining1020009.
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Controlling rockfall-related risks is a requirement for safe pit operations and primarily mitigated through adequate bench geometry design and implementation. This paper presents a method for rockfall hazard analysis for in-pit operations potentially impacting external sensible areas, adapted from natural rockfall hazard analyses. The method considers the natural susceptibility to rockfalls pre-mining, rockfalls originated from bench failures, and those initiated as flyrock. Rockfall trajectory models are used to estimate the potential for blocks reaching exposed elements. Natural susceptibility to rockfalls and trajectories are used as a baseline on which to evaluate the potential effects of open pit operations on the environment and perceptions of communities in the area. The method is illustrated for an open pit in steep terrain in the Peruvian Andes at a feasibility level of study. The paper illustrates the flexibility for including considerations of pre-mining rockfall impacts on the external elements of interest, and for developing rockfall mitigation strategies that consider rock block velocities, heights, energies and the spatial distribution of trajectories. The results highlight the importance of considering the three-dimensional effects of the terrain on block trajectories, and how such insights allow for increasing the efficiency of resources available for rockfall protection structures.
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Hantz, Didier, Jordi Corominas, Giovanni B. Crosta, and Michel Jaboyedoff. "Definitions and Concepts for Quantitative Rockfall Hazard and Risk Analysis." Geosciences 11, no. 4 (April 1, 2021): 158. http://dx.doi.org/10.3390/geosciences11040158.
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There is an increasing need for quantitative rockfall hazard and risk assessment that requires a precise definition of the terms and concepts used for this particular type of landslide. This paper suggests using terms that appear to be the most logic and explicit as possible and describes methods to derive some of the main hazards and risk descriptors. The terms and concepts presented concern the rockfall process (failure, propagation, fragmentation, modelling) and the hazard and risk descriptors, distinguishing the cases of localized and diffuse hazards. For a localized hazard, the failure probability of the considered rock compartment in a given period of time has to be assessed, and the probability for a given element at risk to be impacted with a given energy must be derived combining the failure probability, the reach probability, and the exposure of the element. For a diffuse hazard that is characterized by a failure frequency, the number of rockfalls reaching the element at risk per unit of time and with a given energy (passage frequency) can be derived. This frequency is relevant for risk assessment when the element at risk can be damaged several times. If it is not replaced, the probability that it is impacted by at least one rockfall is more relevant.
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Borella, Josh, Mark Quigley, Zoe Krauss, Krystina Lincoln, Januka Attanayake, Laura Stamp, Henry Lanman, Stephanie Levine, Sam Hampton, and Darren Gravley. "Geologic and geomorphic controls on rockfall hazard: how well do past rockfalls predict future distributions?" Natural Hazards and Earth System Sciences 19, no. 10 (October 11, 2019): 2249–80. http://dx.doi.org/10.5194/nhess-19-2249-2019.
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Abstract. To evaluate the geospatial hazard relationships between recent (contemporary) rockfalls and their prehistoric predecessors, we compare the locations, physical characteristics, and lithologies of rockfall boulders deposited during the 2010–2011 Canterbury earthquake sequence (CES) (n=185) with those deposited prior to the CES (n=1093). Population ratios of pre-CES to CES boulders at two study sites vary spatially from ∼5:1 to 8.5:1. This is interpreted to reflect (i) variations in CES rockfall flux due to intra- and inter-event spatial differences in ground motions (e.g., directionality) and associated variations in source cliff responses; (ii) possible variations in the triggering mechanism(s), frequency, flux, record duration, boulder size distributions, and post-depositional mobilization of pre-CES rockfalls relative to CES rockfalls; and (iii) geological variations in the source cliffs of CES and pre-CES rockfalls. On interfluves, CES boulders traveled approximately 100 to 250 m further downslope than prehistoric (pre-CES) boulders. This is interpreted to reflect reduced resistance to CES rockfall transport due to preceding anthropogenic hillslope de-vegetation. Volcanic breccia boulders are more dimensionally equant and rounded, are larger, and traveled further downslope than coherent lava boulders, illustrating clear geological control on rockfall hazard. In valley bottoms, the furthest-traveled pre-CES boulders are situated further downslope than CES boulders due to (i) remobilization of pre-CES boulders by post-depositional processes such as debris flows and (ii) reduction of CES boulder velocities and travel distances by collisional impacts with pre-CES boulders. A considered earth-systems approach is required when using preserved distributions of rockfall deposits to predict the severity and extents of future rockfall events.
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Tanoli, Javed Iqbal, Ningsheng Chen, Ihsan Ullah, Muhammad Qasim, Sajid Ali, Qasim ur Rehman, Umbreen Umber, and Ishtiaq Ahmed Khan Jadoon. "Modified “Rockfall Hazard Rating System for Pakistan (RHRSP)”: An Application for Hazard and Risk Assessment along the Karakoram Highway, Northwest Pakistan." Applied Sciences 12, no. 8 (April 8, 2022): 3778. http://dx.doi.org/10.3390/app12083778.
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Rockfall is a natural mountain hazard posing a severe threat to people, infrastructure, and vehicles along the transportation corridors. In this research, the standard Rockfall Hazard Rating System (RHRS) is slightly modified for the mountainous terrains of Pakistan through the quantification of animal activity along the highways. In the modified Rockfall Hazard and Rating System for Pakistan (RHRSP), animal activity is scored based on permanent and random animal tracks, shallow and higher altitudes, and shoulder width. The model is applied along the Karakoram Highway (KKH), which traverses a suture between Besham and Dasu (≈78 km), for Rockfall hazard and risk assessment mapping. An inventory of rockfalls, topples, and debris slides is compiled at 30 stations. Results show that rockfalls are mostly of the wedge and topple type failures. Fifty-seven percent of the area falls under the very-high to high hazard zone, 18% under moderate hazard, and 25% covers the low to very low hazard zone. Sixty-seven percent of the stretch is at very-high to high risk, distributed from Dubair to Dasu. The main reason for this risk is associated with narrow road width and limited shoulder width for vehicles. The RHRSP model is also applicable for other highways with the same geological and morphological settings.
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Jaboyedoff, M., J. P. Dudt, and V. Labiouse. "An attempt to refine rockfall hazard zoning based on the kinetic energy, frequency and fragmentation degree." Natural Hazards and Earth System Sciences 5, no. 5 (August 11, 2005): 621–32. http://dx.doi.org/10.5194/nhess-5-621-2005.
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Abstract. Rockfall hazard zoning is usually achieved using a qualitative estimate of hazard, and not an absolute scale. In Switzerland, danger maps, which correspond to a hazard zoning depending on the intensity of the considered phenomenon (e.g. kinetic energy for rockfalls), are replacing hazard maps. Basically, the danger grows with the mean frequency and with the intensity of the rockfall. This principle based on intensity thresholds may also be applied to other intensity threshold values than those used in Switzerland for rockfall hazard zoning method, i.e. danger mapping. In this paper, we explore the effect of slope geometry and rockfall frequency on the rockfall hazard zoning. First, the transition from 2D zoning to 3D zoning based on rockfall trajectory simulation is examined; then, its dependency on slope geometry is emphasized. The spatial extent of hazard zones is examined, showing that limits may vary widely depending on the rockfall frequency. This approach is especially dedicated to highly populated regions, because the hazard zoning has to be very fine in order to delineate the greatest possible territory containing acceptable risks.
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Charalambous, S., and M. Sakellariou. "Estimation of rockfall hazard using a GIS-based three-dimensional rockfall simulation model." Bulletin of the Geological Society of Greece 40, no. 4 (January 1, 2007): 1934. http://dx.doi.org/10.12681/bgsg.17223.
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Rockfall is a very common geomorphological process, yet a major hazard mainly in mountainous areas or along man-made slopes, potentially threatening lives, settlements, equipment, facilities and road infrastructure. In Greece, rockfalls are considered to be one of the most common forms of landslide as well as the most common failure mode likely to be triggered by a seismic event. Rockfall hazard assessment is requisite for both safety purposes (countermeasure design), as well as for land planning purposes. In this paper, a new three-dimensional rockfall simulation model, developed in GIS environment, is proposed as a tool for assessing rockfall hazard for a local- or even a regional-scale area. The application provides stochastic analysis, three-dimensional visualization and animation of rockfalls, by taking advantage of the capabilities offered by GIS. By means of case studies we evaluate the simulation model as a tool assisting spatial analysis and planning, which can be used in decision-making and design concerning road infrastructures, or even a large technical work, such as a dam.
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Crosta, G. B., and F. Agliardi. "A methodology for physically based rockfall hazard assessment." Natural Hazards and Earth System Sciences 3, no. 5 (October 31, 2003): 407–22. http://dx.doi.org/10.5194/nhess-3-407-2003.
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Abstract. Rockfall hazard assessment is not simple to achieve in practice and sound, physically based assessment methodologies are still missing. The mobility of rockfalls implies a more difficult hazard definition with respect to other slope instabilities with minimal runout. Rockfall hazard assessment involves complex definitions for "occurrence probability" and "intensity". This paper is an attempt to evaluate rockfall hazard using the results of 3-D numerical modelling on a topography described by a DEM. Maps portraying the maximum frequency of passages, velocity and height of blocks at each model cell, are easily combined in a GIS in order to produce physically based rockfall hazard maps. Different methods are suggested and discussed for rockfall hazard mapping at a regional and local scale both along linear features or within exposed areas. An objective approach based on three-dimensional matrixes providing both a positional "Rockfall Hazard Index" and a "Rockfall Hazard Vector" is presented. The opportunity of combining different parameters in the 3-D matrixes has been evaluated to better express the relative increase in hazard. Furthermore, the sensitivity of the hazard index with respect to the included variables and their combinations is preliminarily discussed in order to constrain as objective as possible assessment criteria.
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Gomes, Guilherme J. C., Frederico G. Sobreira, and Milene S. Lana. "Evaluation of Rockfall Hazard Along Brazil Roads." Soils and Rocks 34, no. 2 (May 1, 2011): 163–74. http://dx.doi.org/10.28927/sr.342163.
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. The Brazilian road network is constructed in a highly heterogeneous geological environment and some stretches cross through discontinuous rock masses that have uncertain or even ignored geotechnical characteristics. Rock slopes are potentially unstable surfaces and as such are susceptible to rockfalls that affect the highway’s user safety, transportation infrastructure and surrounding environment. The geomechanical behavior of rock masses and also the geometric and traffic conditions of highways are fundamental aspects of rockfall evaluation. This research presents a case study of rockfall evaluation for slopes bordering highway sections, aiming to classify them and determine a hierarchy for intervention, based on defined criteria. The presented method could be used as a first step in the study of stabilization techniques for problems caused by rockfalls from highway slopes. In order to use this approach, field investigations including geomechanical classification of rock mass are necessary. In this context, twelve slope sections containing rock slopes in Espirito Santo’s road network were investigated. The slopes were analyzed individually and the influence of each parameter in the global rating was evaluated. Parameter effectiveness in the proposed method was also evaluated. The slopes were classified to define priority measures to minimize roadway problems in each place.
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Lalhlimpuia, H., Zairemmawii, Shiva Kumar, and Laldinpuia. "RMR and RHRS of Ngaizel Road cutting section, Aizawl, Mizoram." Senhri Journal of Multidisciplinary Studies 4, no. 2 (December 28, 2019): 7–21. http://dx.doi.org/10.36110/sjms.2019.04.02.002.
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Due to unfavourable topographical features roads in hilly areas are usually small as compared to plain areas, therefore several problems may arise whenever rockfall occurs. One of the busiest domestic road in Aizawl i.e. Ngaizel road often encountered rockfall along its cutting slope. This road act as an important gateway which connects the southern parts of Mizoram. This road is packed with human activities which adds on the hazard level to rise high. The main factors that contribute to rockfalls include slope degree, geomechanical properties of rock mass and anthropogenic activities. Taking into consideration of all the adverse effect of rockfalls, RMR (Rock Mass Rating) become indispensable to identify the actual condition of rock mass on the slope of the study area. RMR classification is carried out to determine the geomechanical condition of slope rock mass and Rockfall Hazard Rating System (RHRS) is applied for identifying the hazard-prone area of rockfall along the cut slope of Ngaizel road. RHRS depends on various parameter which include slope height, annual precipitation, block size, block volume, decision sight distance, average vehicle risk, road width and rockfall history which mainly concern about the safety of pedestrians along the road. The RMR and RHRS study along Ngaizel cut slope provides a detailed and useful information about the geological condition and delineating the hazard level. The study also gave awareness and alertness about the actual condition of the area.
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Mineo, Simone, Giovanna Pappalardo, Michele Mangiameli, Santo Campolo, and Giuseppe Mussumeci. "Rockfall Analysis for Preliminary Hazard Assessment of the Cliff of Taormina Saracen Castle (Sicily)." Sustainability 10, no. 2 (February 6, 2018): 417. http://dx.doi.org/10.3390/su10020417.
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A rockfall analysis at one of the most relevant cultural heritage sites of northeastern Sicily (Italy) is presented herein with the aim of assessing the hazard arising from the unstable conditions of the rock cliff of Taormina city, upon which the Saracen Castle is perched on its top. Several rockfalls affected this area in the latest years, representing a serious threat for the safety of inhabitants and tourists. Therefore, the qualitative Evolving Rockfall Hazard Assessment (ERHA) was applied for the hazard zonation, supported by rock mass surveys and Terrestrial Laser Scanner prospecting. Kinematic analysis revealed that the unstable rock failure patterns are represented by planar/wedge sliding and toppling, while simulation of potential rockfalls allowed studying the impact of future events in terms of trajectory and energy. This is higher at the foot of scarps and in steeper sectors, where the application of ERHA identified a critical zone close to the inhabited center, which is one of the main elements at risk, along with a pedestrian tourist path. Achieved results represent a starting point for the definition of risk management strategies and provide a scientific contribution to the study of hazard and risk arising from rockfall occurrence.
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Chen, Yuan Chuan, Jia Kun Li, and Ling Gang Ran. "A Review of Rockfall Control Measures along Highway." Applied Mechanics and Materials 353-356 (August 2013): 2385–91. http://dx.doi.org/10.4028/www.scientific.net/amm.353-356.2385.
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Rockfalls are a constant danger to motorists and to highway facilities in mountainous terrain. Rockfall disaster displays some features such as wide distribution, much quantity, sudden occurrence, randomicity and strong fatalness. Against rockfall hazard along highway, there are two types of protection: passive ones and active ones. In present paper, the authors conduct a systematically summary of rockfall control measures along highway. Seven kinds of key active methods and six kinds of vital passive technologies to prevent and cure rockfall are presented. This review is of certain reference value for road maintenance in rocky mountains.
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Mueller, S. B., N. R. Varley, U. Kueppers, P. Lesage, G. Á. Reyes Davila, and D. B. Dingwell. "Quantification of magma ascent rate through rockfall monitoring at the growing/collapsing lava dome of Volcán de Colima, Mexico." Solid Earth Discussions 5, no. 1 (January 15, 2013): 1–39. http://dx.doi.org/10.5194/sed-5-1-2013.
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Abstract. The most recent eruptive phase of Volcán de Colima, Mexico, started in 1998 and was characterized by episodic dome growth with a variable effusion rate, interrupted intermittently by explosive eruptions. Between November 2009 and June 2011, growth at the dome was limited to a lobe on the western side where it had previously started overflowing the crater rim, leading to the generation of rockfall events. This meant that no significant increase in dome volume was perceivable and the rate of magma ascent, a crucial parameter for volcano monitoring and hazard assessment, could no longer be quantified via measurements of the dome's dimensions. Here, we present alternative approaches to quantify the magma ascent rate. We estimate the volume of individual rockfalls through the detailed analysis of sets of photographs (before and after individual rockfall events). The relationship between volume and infrared images of the freshly exposed dome surface and the seismic signals related to the rockfall events was then investigated. Larger events exhibited a correlation between the previously estimated volume of a rockfall and the surface temperature of the freshly exposed dome surface as well as the mean temperature of rockfall masses distributed over the slope. We showed that for larger events, the volume of the rockfall correlates with the maximum temperature at the newly formed cliff as well as the seismic energy. By calibrating the seismic signals using the volumes estimated from photographs, the count of rockfalls over a certain period was used to estimate the magma extrusion flux for the period investigated. Over the course of the measurement period, significant changes were observed in number of rockfalls, rockfall volume and hence averaged extrusion rate. The extrusion rate was not constant: it increased from 0.008 m3 s−1 to 0.02 m3 s−1 during 2010 and dropped down to 0.008 m3 s−1 again in March 2011. In June 2011, magma extrusion had come to a halt. The methodology presented represents a reliable tool to constrain the growth rate of domes that are repeatedly affected by partial collapses. There is a good correlation between thermal and seismic energies and rockfall volume. Thus it is possible to calibrate the seismic records associated with the rockfalls (a continuous monitoring tool) to improve both volcano monitoring at volcanoes with active dome growth and hazard management associated with rockfalls specifically.
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Massey, Chris I., Mauri J. McSaveney, Tony Taig, Laurie Richards, Nicola J. Litchfield, David A. Rhoades, Graeme H. McVerry, et al. "Determining Rockfall Risk in Christchurch Using Rockfalls Triggered by the 2010–2011 Canterbury Earthquake Sequence." Earthquake Spectra 30, no. 1 (February 2014): 155–81. http://dx.doi.org/10.1193/021413eqs026m.
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The Canterbury earthquake sequence triggered thousands of rockfalls in the Port Hills of Christchurch, New Zealand, with over 6,000 falling on 22 February 2011. Several hundred families were evacuated after about 200 homes were hit. We characterized the rockfalls by boulder-size distribution, runout distance, source-area dimensions, and boulder-production rates over a range of triggering peak ground accelerations. Using these characteristics, a time-varying seismic hazard model for Canterbury, and estimates of residential occupancy rates and resident vulnerability, we estimated annual individual fatality risk from rockfall in the Port Hills. The results demonstrate the Port Hills rockfall risk is time-variable, decreasing as the seismic hazard decreases following the main earthquakes in February and June 2011. This presents a real challenge for formulating robust land-use and reconstruction policy in the Port Hills.
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Liu, Ming, and Jie Chen. "Movement and Protection for Random Shape Rockfalls in Steeply Dipping Coal Seams." Advances in Civil Engineering 2021 (October 12, 2021): 1–14. http://dx.doi.org/10.1155/2021/9965415.
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In view of the randomness of rockfalls shape and irregularity of the bottom floor of working face in steeply dipping coal seams (SDCS), it is difficult to accurately simulate rockfall movement, and it is consequently unable to effectively protect against multirockfalls. Therefore, a method for generating random shape rockfalls based on ellipsoid equation is proposed, and a 3D grid model of real bottom floor of working face is established based on the geographic information system data. In order to verify the accuracy and feasibility of the method and 3D model, the trajectory simulated by Rockyfor3D software is compared, and the proposed method and 3D model prove to be effective in simulating rockfall movement more accurately. Then the proposed method and 3D grid model are applied to solve the problem of multirockfalls protection in numerical simulation, and the main factors affecting the structural stress response of protective netting are analyzed by taking three incident modes of parallel heights, ladder parallel, and the same trajectory. In the simulation, it is found out that the trajectory of irregular rockfalls is greatly affected by the shape of rockfall and working face floor; during the process of multiple rockfalls colliding with the protective netting, the peak stress on the protective netting is inversely proportional to both the time interval between each rockfall and the distance between each rockfall. The findings presented in this research contribute to rockfall prediction and protection against rockfall hazards.
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Dietze, Michael, Jens M. Turowski, Kristen L. Cook, and Niels Hovius. "Spatiotemporal patterns, triggers and anatomies of seismically detected rockfalls." Earth Surface Dynamics 5, no. 4 (November 29, 2017): 757–79. http://dx.doi.org/10.5194/esurf-5-757-2017.
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Abstract. Rockfalls are a ubiquitous geomorphic process and a natural hazard in steep landscapes across the globe. Seismic monitoring can provide precise information on the timing, location and event anatomy of rockfalls, which are parameters that are otherwise hard to constrain. By pairing data from 49 seismically detected rockfalls in the Lauterbrunnen Valley in the Swiss Alps with auxiliary meteorologic and seismic data of potential triggers during autumn 2014 and spring 2015, we are able to (i) analyse the evolution of single rockfalls and their common properties, (ii) identify spatial changes in activity hotspots (iii) and explore temporal activity patterns on different scales ranging from months to minutes to quantify relevant trigger mechanisms. Seismic data allow for the classification of rockfall activity into two distinct phenomenological types. The signals can be used to discern multiple rock mass releases from the same spot, identify rockfalls that trigger further rockfalls and resolve modes of subsequent talus slope activity. In contrast to findings based on discontinuous methods with integration times of several months, rockfall in the monitored limestone cliff is not spatially uniform but shows a systematic downward shift of a rock mass release zone following an exponential law, most likely driven by a continuously lowering water table. Freeze–thaw transitions, approximated at first order from air temperature time series, account for only 5 out of the 49 rockfalls, whereas 19 rockfalls were triggered by rainfall events with a peak lag time of 1 h. Another 17 rockfalls were triggered by diurnal temperature changes and occurred during the coldest hours of the day and during the highest temperature change rates. This study is thus the first to show direct links between proposed rockfall triggers and the spatiotemporal distribution of rockfalls under natural conditions; it extends existing models by providing seismic observations of the rockfall process prior to the first rock mass impacts.
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Borella, Josh Walter, Mark Quigley, and Louise Vick. "Anthropocene rockfalls travel farther than prehistoric predecessors." Science Advances 2, no. 9 (September 2016): e1600969. http://dx.doi.org/10.1126/sciadv.1600969.
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Human modification of natural landscapes has influenced surface processes in many settings on Earth. Quantitative data comparing the distribution and behavior of geologic phenomena before and after human arrival are sparse but urgently required to evaluate possible anthropogenic influences on geologic hazards. We conduct field and imagery-based mapping, statistical analysis, and numerical modeling of rockfall boulders triggered by the fatal 2011 Christchurch earthquakes (n= 285) and newly identified prehistoric (Holocene and Pleistocene) boulders (n= 1049). Prehistoric and modern boulders are lithologically equivalent, derived from the same source cliff, and yield consistent power-law frequency-volume distributions. However, a significant population of modern boulders (n= 26) traveled farther downslope (>150 m) than their most-traveled prehistoric counterparts, causing extensive damage to residential dwellings at the foot of the hillslope. Replication of prehistoric boulder distributions using three-dimensional rigid-body numerical models that incorporate lidar-derived digital topography and realistic boulder trajectories and volumes requires the application of a drag coefficient, attributed to moderate to dense slope vegetation, to account for their spatial distribution. Incorporating a spatially variable native forest into the models successfully predicts prehistoric rockfall distributions. Radiocarbon dating provides evidence for 17th to early 20th century deforestation at the study site during Polynesian and European colonization and after emplacement of prehistoric rockfall. Anthropocene deforestation enabled modern rockfalls to exceed the limits of their prehistoric predecessors, highlighting a shift in the geologic expression of rockfalls due to anthropogenic activity. Reforestation of hillslopes by mature native vegetation could help reduce future rockfall hazard.
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Mourey, Jacques, Pascal Lacroix, Pierre-Allain Duvillard, Guilhem Marsy, Marco Marcer, Emmanuel Malet, and Ludovic Ravanel. "Multi-method monitoring of rockfall activity along the classic route up Mont Blanc (4809 m a.s.l.) to encourage adaptation by mountaineers." Natural Hazards and Earth System Sciences 22, no. 2 (February 16, 2022): 445–60. http://dx.doi.org/10.5194/nhess-22-445-2022.
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Abstract. There are on average 35 fatal mountaineering accidents per summer in France. On average, since 1990, 3.7 of them have occurred every summer in the Grand Couloir du Goûter, on the classic route up Mont Blanc (4809 m a.s.l.). Rockfall is one of the main factors that explain this high accident rate and contribute to making it one of the most accident-prone areas in the Alps for mountaineers. In this particular context, the objective of this study is to document the rockfall activity and its triggering factors in the Grand Couloir du Goûter in order to disseminate the results to mountaineers and favour their adaptation to the local rockfall hazard. Using a multi-method monitoring system (five seismic sensors, an automatic digital camera, three rock subsurface temperature sensors, a traffic sensor, a high-resolution topographical survey, two weather stations and a rain gauge), we acquired a continuous database on rockfalls during a period of 68 d in 2019 and some of their potential triggering factors (precipitation, ground and air temperatures, snow cover, frequentation by climbers). At the seasonal scale, our results confirm previous studies showing that rockfalls are most frequent during the snowmelt period in permafrost-affected rockwalls. Furthermore, the unprecedented time precision and completeness of our rockfall database at high elevation thanks to seismic sensors allowed us to investigate the factors triggering rockfalls. We found a clear correlation between rockfall frequency and air temperature, with a 2 h delay between peak air temperature and peak rockfall activity. A small number of rockfalls seem to be triggered by mountaineers. Our data set shows that climbers are not aware of the variations in rockfall frequency and/or cannot/will not adapt their behaviour to this hazard. These results should help to define an adaptation strategy for climbers. Therefore, we disseminated our results within the mountaineering community thanks to the full integration of our results into the management of the route by local actors. Knowledge built during this experiment has already been used for the definition and implementation of management measures for the attendance in summer 2020.
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Delonca, A., Y. Gunzburger, and T. Verdel. "Assessment of rockfall hazards using databases and considering triggering meteorological events." Natural Hazards and Earth System Sciences Discussions 2, no. 2 (February 10, 2014): 1333–65. http://dx.doi.org/10.5194/nhessd-2-1333-2014.
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Abstract. Rockfalls are major and essentially unpredictable sources of danger, particularly along transportation routes (roads and railways). Thus, assessment of their probabilities of occurrence is a major challenge for risk management. From a qualitative perspective, experience has shown that rockfalls occur mainly during periods of rain, snowmelt, or freeze–thaw. Nevertheless, from a quantitative perspective, these generally assumed correlations between rockfalls and their possible meteorological triggering events are often difficult to identify because (i) rockfalls are too rare for the use of classical statistical analysis techniques and (ii) all intensities of triggering factors do not have the same probability. In this study, we propose a new approach to investigate the correlation of rockfalls with rain, freezing periods, and strong temperature variations. This approach is tested on three French rockfall databases, the first of which exhibited a high frequency of rockfalls (approximately 950 events over 11 yr), whereas the other two databases were more common (approximately 140 events over 11 yr). These databases were for (1) the national highway RN1 on La-Réunion Island, (2) a railway in the Bourgogne region, and (3) a railway in the Auvergne region. Whereas a basic correlation analysis is only able to highlight an already obvious correlation in the case of the "rich" database, the newly suggested method appears to detect correlations in the "poor" databases. This new approach, easy to use, leads to identify the conditional probability of rockfall, according to the selected meteorological factor. It will help to optimize risk management in the considered areas with respect to their meteorological conditions.
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Masuya, H., K. Amanuma, Y. Nishikawa, and T. Tsuji. "Basic rockfall simulation with consideration of vegetation and application to protection measure." Natural Hazards and Earth System Sciences 9, no. 6 (November 10, 2009): 1835–43. http://dx.doi.org/10.5194/nhess-9-1835-2009.
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Abstract. The estimation of risk due to rockfall is often done empirically. As a rational and effective method towards performance-based design of protection measures, a three-dimensional simulation method helps to describe the motion of rockfall on a slope and to consider the effect of vegetation probabilistically. This document details a typical simulation method and analyses the manner of rockfalls paired with interference of vegetation and other factors. As application, an actual slope is analyzed where rockfall occurred during the Noto Peninsula Earthquake. Finally, the validity and the benefits of the shown method are the basis for a hazard mapping for rockfall and the planning of measures.
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Aqeel, Adnan M. "Rockfall Hazard Rating System(s) in Saudi Arabia – A Review." Journal of Geography and Geology 10, no. 4 (November 9, 2018): 1. http://dx.doi.org/10.5539/jgg.v10n4p1.
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Slope instability along highways in mountainous areas is not only a major hazard for lives and passing vehicles but also may hinder traffic for long period and thus create significant economic loss. The most common type of slope instability failures in such areas is rockfalls. Many qualitative rockfall hazard rating systems (RHRSs) have been developed across the world. However, the Middle East almost lacks to such systems. For instance, in Saudi Arabia, which has the largest economy in the region, only one system of rockfall hazard rating system (RHRS-SA) has been developed up to now. This paper aimed to critically review this system. Some drawbacks were found in the RHRS-SA. However, the main disadvantage was that the final rating score of risk is not consistent with risk definition. In sum, the remarkable findings of this review can be accounted either for any future modifications for the RHRS-SA or to develop a new rockfall hazard rating system but for a specific area(s) in Saudi Arabia.
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Rahmati, Omid, Saleh Yousefi, Zahra Kalantari, Evelyn Uuemaa, Teimur Teimurian, Saskia Keesstra, Tien Pham, and Dieu Tien Bui. "Multi-Hazard Exposure Mapping Using Machine Learning Techniques: A Case Study from Iran." Remote Sensing 11, no. 16 (August 20, 2019): 1943. http://dx.doi.org/10.3390/rs11161943.
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Mountainous areas are highly prone to a variety of nature-triggered disasters, which often cause disabling harm, death, destruction, and damage. In this work, an attempt was made to develop an accurate multi-hazard exposure map for a mountainous area (Asara watershed, Iran), based on state-of-the art machine learning techniques. Hazard modeling for avalanches, rockfalls, and floods was performed using three state-of-the-art models—support vector machine (SVM), boosted regression tree (BRT), and generalized additive model (GAM). Topo-hydrological and geo-environmental factors were used as predictors in the models. A flood dataset (n = 133 flood events) was applied, which had been prepared using Sentinel-1-based processing and ground-based information. In addition, snow avalanche (n = 58) and rockfall (n = 101) data sets were used. The data set of each hazard type was randomly divided to two groups: Training (70%) and validation (30%). Model performance was evaluated by the true skill score (TSS) and the area under receiver operating characteristic curve (AUC) criteria. Using an exposure map, the multi-hazard map was converted into a multi-hazard exposure map. According to both validation methods, the SVM model showed the highest accuracy for avalanches (AUC = 92.4%, TSS = 0.72) and rockfalls (AUC = 93.7%, TSS = 0.81), while BRT demonstrated the best performance for flood hazards (AUC = 94.2%, TSS = 0.80). Overall, multi-hazard exposure modeling revealed that valleys and areas close to the Chalous Road, one of the most important roads in Iran, were associated with high and very high levels of risk. The proposed multi-hazard exposure framework can be helpful in supporting decision making on mountain social-ecological systems facing multiple hazards.
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Kreiniuk, Mark, and Nikolay Belyaev. "Investigation of Natural Hazards: Theoretical and Practical Models." Applied Mechanics and Materials 725-726 (January 2015): 1090–100. http://dx.doi.org/10.4028/www.scientific.net/amm.725-726.1090.
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Different types of methods needed to determinate risk of natural hazards on the field for different types of hazards. Avalanche and rockfall act the same, get acceleration from gravity depend on slope. It mostly often that they both possible in mountain region around the earth. But behavior of this processes is different and consequences are also different. To predict rockfalls and avalanches we have to create method which can be compared with reality. Compare model versus reality possible in areas with many years of observations. So we can use thisa model to simulate behavior of rockfalls and avalanches in not studied areas.
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Al-Shaar, Mohammad, Pierre-Charles Gérard, Ghaleb Faour, Walid Al-Shaar, and Jocelyne Adjizian-Gérard. "Comparison of Earthquake and Moisture Effects on Rockfall-Runouts Using 3D Models and Orthorectified Aerial Photos." Geographies 3, no. 1 (January 16, 2023): 110–29. http://dx.doi.org/10.3390/geographies3010006.
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Rockfall hazard gains popularity nowadays among researchers in different scientific fields, decision-makers and urban planners. The assessment of rockfall hazard requires detection, mapping and estimating the maximum travel distance that rock boulders may reach, commonly known as “rockfall runout”. This latter can change significantly under the effects of different triggering factors such as soil conditions, chemical, physical and geological rock properties. However, comparing and analyzing these different effects represents, to the best of our knowledge, one of the newest scientific challenges that need to be addressed. This paper presents a complete methodologic approach aiming to assess the rockfall hazard through runout estimation in three different conditions: (i) gravity, (ii) earthquakes, and (iii) the presence of moisture along the slope. The “Mtein” Village and its surrounding areas in the Mount Lebanon region were chosen as the study area because there have been numerous historic rockfalls and various-sized rocks, such as cobbles and boulders, scattered throughout the area. Thus, three-dimensional simulations were conducted using the Rockyfor3D software and aerial photos for the year 1999 to assess the rockfall runout, the energy curves, and the number of deposited rocks. The results reveal that earthquakes have the highest triggering effect on rockfall and that moisture has a damping effect on RFs by decreasing the kinetic energy. The study shows the importance of taking into consideration the influence of triggering factors as well as rock density on rockfall runout and hazard.
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Admassu, Yonathan. "Digital Surface Model-aided Quantitative Geologic Rockfall Rating System (QG-RRS)." Environmental and Engineering Geoscience 25, no. 4 (November 8, 2019): 255–71. http://dx.doi.org/10.2113/eeg-2102.
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ABSTRACT Rockfalls are one of the most common types of slope failures that affect cut slopes along roadways in mountainous regions. The Rockfall Hazard Rating System (RHRS), started in Oregon and adopted by various U.S. states, is used to rate cut slopes with respect to their likelihood of releasing rockfalls. Existing rating systems use semi-quantitative approaches to rate geological and non-geological factors. The main geologic factors are favorability/unfavorability of orientation of discontinuities with respect to the orientation of slope faces and likelihood of differential weathering leading to undercutting of strong rock units. Digital surface models (DSMs) derived from light detection and ranging (LiDAR) and photogrammetry have been used to remotely characterize rock mass. This research introduces an expanded application of DSMs to quantify geologic factors that contribute to the likelihood of rockfall events. The method is hence referred to as the Quantitative Geologic Rockfall Rating System (QG-RRS). Four DSM-based parameters, A, B, C, and D, have been identified to evaluate geologic factors. These parameters quantify the likelihood of discontinuity orientation-controlled failures (parameter A), the degree of undercutting (parameter B), rockfall activity based on rockfall release surfaces (parameter C), and rockfall volume from rockfall voids (parameter D). This rating system, although not inclusive of other non-geological factors, appears to provide reproducible quantitative estimation of geologic factors that control rockfall generation.
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Michoud, C., M. H. Derron, P. Horton, M. Jaboyedoff, F. J. Baillifard, A. Loye, P. Nicolet, A. Pedrazzini, and A. Queyrel. "Rockfall hazard and risk assessments along roads at a regional scale: example in Swiss Alps." Natural Hazards and Earth System Sciences 12, no. 3 (March 14, 2012): 615–29. http://dx.doi.org/10.5194/nhess-12-615-2012.
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Abstract. Unlike fragmental rockfall runout assessments, there are only few robust methods to quantify rock-mass-failure susceptibilities at regional scale. A detailed slope angle analysis of recent Digital Elevation Models (DEM) can be used to detect potential rockfall source areas, thanks to the Slope Angle Distribution procedure. However, this method does not provide any information on block-release frequencies inside identified areas. The present paper adds to the Slope Angle Distribution of cliffs unit its normalized cumulative distribution function. This improvement is assimilated to a quantitative weighting of slope angles, introducing rock-mass-failure susceptibilities inside rockfall source areas previously detected. Then rockfall runout assessment is performed using the GIS- and process-based software Flow-R, providing relative frequencies for runout. Thus, taking into consideration both susceptibility results, this approach can be used to establish, after calibration, hazard and risk maps at regional scale. As an example, a risk analysis of vehicle traffic exposed to rockfalls is performed along the main roads of the Swiss alpine valley of Bagnes.
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van Veen, Megan, D. Jean Hutchinson, David A. Bonneau, Zac Sala, Matthew Ondercin, and Matt Lato. "Combining temporal 3-D remote sensing data with spatial rockfall simulations for improved understanding of hazardous slopes within rail corridors." Natural Hazards and Earth System Sciences 18, no. 8 (August 29, 2018): 2295–308. http://dx.doi.org/10.5194/nhess-18-2295-2018.
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Abstract. Remote sensing techniques can be used to gain a more detailed understanding of hazardous rock slopes along railway corridors that would otherwise be inaccessible. Multiple datasets can be used to identify changes over time, creating an inventory of events to produce magnitude–frequency relationships for rockfalls sourced on the slope. This study presents a method for using the remotely sensed data to develop inputs to rockfall simulations, including rockfall source locations and slope material parameters, which can be used to determine the likelihood of a rockfall impacting the railway tracks given its source zone location and volume. The results of the simulations can be related to the rockfall inventory to develop modified magnitude–frequency curves presenting a more realistic estimate of the hazard. These methods were developed using the RockyFor3D software and lidar and photogrammetry data collected over several years at White Canyon, British Columbia, Canada, where the Canadian National (CN) Rail main line runs along the base of the slope. Rockfalls sourced closer to the tracks were more likely to be deposited on the track or in the ditch, and of these, rockfalls between 0.1 and 10 m3 were the most likely to be deposited. Smaller blocks did not travel far enough to reach the bottom of the slope and larger blocks were deposited past the tracks. Applying the results of the simulations to a database of over 2000 rockfall events, a modified magnitude–frequency can be created, allowing the frequency of rockfalls deposited on the railway tracks or in ditches to be determined. Suggestions are made for future development of the methods including refinement of input parameters and extension to other modelling packages.
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Budetta, P., and M. Nappi. "Comparison between qualitative rockfall risk rating systems for a road affected by high traffic intensity." Natural Hazards and Earth System Sciences 13, no. 6 (June 22, 2013): 1643–53. http://dx.doi.org/10.5194/nhess-13-1643-2013.
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Abstract. The paper deals with the assessment of the rockfall risk for a road stretch, in southern Italy, affected by high traffic intensity. Three qualitative rockfall risk rating systems (QRSs) which use an exponential scoring with a base of 3 were employed, and then the results were compared. The used methods are the following: the Rockfall Hazard Rating System, a modified version of this method already proposed in the past by one of the authors, and the modified version of the Colorado Rockfall Hazard Rating System. The studied road stretch is about 11 km in length and is part of a very tortuous road flanked by rock slopes characterised by complex geostructural and geomechanical layouts. The road was subdivided into 56 sections, defined so as to have – as much as possible – homogeneous geological characteristics. By means of the three QRSs, it was possible to ascertain that high levels of rockfall risks are due to the lack of ditches, a very limited percentage of decision sight distance (PDSD) values and a small roadway width, whereas a subordinate factor is the hazard caused by rockfalls. Several positive and negative aspects arising from the use of the employed methods are highlighted and discussed.
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Copons, R., J. M. Vilaplana, and R. Linares. "Rockfall travel distance analysis by using empirical models (Solà d'Andorra la Vella, Central Pyrenees)." Natural Hazards and Earth System Sciences 9, no. 6 (December 14, 2009): 2107–18. http://dx.doi.org/10.5194/nhess-9-2107-2009.
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Abstract. The prediction of rockfall travel distance below a rock cliff is an indispensable activity in rockfall susceptibility, hazard and risk assessment. Although the size of the detached rock mass may differ considerably at each specific rock cliff, small rockfall (<100 m3) is the most frequent process. Empirical models may provide us with suitable information for predicting the travel distance of small rockfalls over an extensive area at a medium scale (1:100 000–1:25 000). "Solà d'Andorra la Vella" is a rocky slope located close to the town of Andorra la Vella, where the government has been documenting rockfalls since 1999. This documentation consists in mapping the release point and the individual fallen blocks immediately after the event. The documentation of historical rockfalls by morphological analysis, eye-witness accounts and historical images serve to increase available information. In total, data from twenty small rockfalls have been gathered which reveal an amount of a hundred individual fallen rock blocks. The data acquired has been used to check the reliability of the main empirical models widely adopted (reach and shadow angle models) and to analyse the influence of parameters which affecting the travel distance (rockfall size, height of fall along the rock cliff and volume of the individual fallen rock block). For predicting travel distances in maps with medium scales, a method has been proposed based on the "reach probability" concept. The accuracy of results has been tested from the line entailing the farthest fallen boulders which represents the maximum travel distance of past rockfalls. The paper concludes with a discussion of the application of both empirical models to other study areas.
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Prina Howald, Erika, Jacopo Maria Abbruzzese, and Chiara Grisanti. "An approach for evaluating the role of protection measures in rockfall hazard zoning based on the Swiss experience." Natural Hazards and Earth System Sciences 17, no. 7 (July 11, 2017): 1127–44. http://dx.doi.org/10.5194/nhess-17-1127-2017.
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Abstract. Rockfall hazard zoning is essential for ensuring the safety of communities settled at the toe of potentially unstable slopes. Rockfall hazard zoning can be performed to include the effect of protection measures when land use restrictions might not be enough to mitigate hazards. The real effectiveness of the measures must be assessed to make sure they can play their role, especially in those cases when measures might have been installed at a given site for years. This article focuses on how to evaluate the effectiveness of rockfall protection measures and how hazard zoning can be influenced by their correct operation. The approach presented is divided into four main stages, which include a two-step procedure to evaluate the effectiveness of both existing and new protections. It is based on quite a comprehensive rockfall protection database built for the canton of Vaud in Switzerland, and on the Swiss Federal Guidelines for hazard zoning; however, all the methodological framework proposed and related considerations could be in principle extended to any other regional or national context in which a combination of intensity and frequency is used to assess rockfall hazards.
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Swanger, William, and Yonathan Admassu. "Using Google Earth and Google Street View To Rate Rock Slope Hazards." Environmental and Engineering Geoscience 24, no. 2 (May 23, 2018): 237–50. http://dx.doi.org/10.2113/eeg-1922.
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Abstract Rockfall hazard from cut slopes along highways are caused primarily by unfavorable orientations of discontinuities, presence of unconsolidated cobble/boulder deposits, undercutting of strong rocks by weaker rocks, or degradation of weak rock masses. The rockfall hazard rating system (RHRS) was introduced in Oregon to evaluate the hazard and associated risk to an adjacent transportation facility for a cut slope's potential for releasing rockfalls. RHRS is a numerical score–based rating of parameters that characterize rockfalls. The parameters include slope geometry (height, angle, roughness, orientation), geologic information (discontinuity characterization, undercutting susceptibility), driver's line of sight, and climate. Geologic information, such as discontinuity orientation data, is traditionally collected using a transit compass and measuring tape at the site. The method is time consuming and expensive and can be dangerous. This study tests the use of Google Earth and Google Street View tools to remotely collect data for selected parameters that characterize rockfall hazard. The selected parameters are categorized under slope profile, geologic characteristics, and impact factor parameters, which are quantitatively and qualitatively measurable using Google Street View and Google Earth. A section of U.S. 33 with a high density of road cuts and two more sites along Interstate 64, all located in Virginia, were selected for the study. Sites were evaluated by using a combination of measurement tools available in Google Earth and a visual inspection of the rock units in Google Street View. The results of seven of the sites were re-evaluated using field-derived data.
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Robiati, Carlo, Giandomenico Mastrantoni, Mirko Francioni, Matthew Eyre, John Coggan, and Paolo Mazzanti. "Contribution of High-Resolution Virtual Outcrop Models for the Definition of Rockfall Activity and Associated Hazard Modelling." Land 12, no. 1 (January 6, 2023): 191. http://dx.doi.org/10.3390/land12010191.
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The increased accessibility of drone technology and structure from motion 3D scene reconstruction have transformed the approach for mapping inaccessible slopes undergoing active rockfalls and generating virtual outcrop models (VOM). The Poggio Baldi landslide (Central Italy) and its natural laboratory offers the possibility to monitor and characterise the slope to define a workflow for rockfall hazard analysis. In this study, the analysis of multitemporal VOM (2016–2019) informed a rockfall trajectory analysis that was carried out with a physical-characteristic-based GIS model. The rockfall scenarios were reconstructed and then tested based on the remote sensing observations of the rock mass characteristics of both the main scarp and the rockfall fragment inventory deposited on the slope. The highest concentration of trajectory endpoints occurred at the very top of the debris talus, which was constrained by a narrow channel, while longer horizontal travel distances were allowed on the lower portion of the slope. To further improve the understanding of the Poggio Baldi landslide, a time-independent rockfall hazard analysis aiming to define the potential runout associated with several rock block volumetric classes is a critical component to any subsequent risk analysis in similar mountainous settings featuring marly–arenaceous multilayer sedimentary successions and reactivated main landslide scarps.
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Manousakis, J., D. Zekkos, F. Saroglou, and M. Clark. "COMPARISON OF UAV-ENABLED PHOTOGRAMMETRY-BASED 3D POINT CLOUDS AND INTERPOLATED DSMs OF SLOPING TERRAIN FOR ROCKFALL HAZARD ANALYSIS." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-2/W2 (October 5, 2016): 71–77. http://dx.doi.org/10.5194/isprs-archives-xlii-2-w2-71-2016.
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UAVs are expected to be particularly valuable to define topography for natural slopes that may be prone to geological hazards, such as landslides or rockfalls. UAV-enabled imagery and aerial mapping can lead to fast and accurate qualitative and quantitative results for photo documentation as well as basemap 3D analysis that can be used for geotechnical stability analyses. In this contribution, the case study of a rockfall near Ponti village that was triggered during the November 17th 2015 M<sub>w</sub> 6.5 earthquake in Lefkada, Greece is presented with a focus on feature recognition and 3D terrain model development for use in rockfall hazard analysis. A significant advantage of the UAV was the ability to identify from aerial views the rockfall trajectory along the terrain, the accuracy of which is crucial to subsequent geotechnical back-analysis. Fast static GPS control points were measured for optimizing internal and external camera parameters and model georeferencing. Emphasis is given on an assessment of the error associated with the basemap when fewer and poorly distributed ground control points are available. Results indicate that spatial distribution and image occurrences of control points throughout the mapped area and image block is essential in order to produce accurate geospatial data with minimum distortions.
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González de Vallejo, Luis I., Luis E. Hernández-Gutiérrez, Ana Miranda, and Mercedes Ferrer. "Rockfall Hazard Assessment in Volcanic Regions Based on ISVS and IRVS Geomechanical Indices." Geosciences 10, no. 6 (June 6, 2020): 220. http://dx.doi.org/10.3390/geosciences10060220.
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In volcanic regions, rockfalls represent a major hazard strongly conditioned by the geomechanical behaviour of volcanic materials, the geomorphological characteristics of the relief and the climatic conditions. Volcanic rocks possess very different properties to those of other lithological groups, presenting highly heterogeneous geomechanical behaviours. Nevertheless, they have received little research attention in the field of geological and geotechnical engineering. To date, the application of geomechanical classifications to characterise and estimate volcanic slope stability has not yielded reliable results, indicating the need to establish specific criteria for these rocks. Consequently, we developed indices to estimate rockfall susceptibility, hazard and risk in volcanic slopes. The index of susceptibility for volcanic slopes (ISVS) is designed to estimate slope susceptibility to instability, which is related to the level of hazard, while the index of risk for volcanic slopes (IRVS) is designed to estimate the level of risk as a function of the potential damage or economic loss caused as a result of rockfalls on slopes. Both indices were developed in order to provide an easily applied procedure that facilitates the adoption of short-term preventive measures against rockfalls. The indices were applied in Tenerife (Canary Islands), which presents exceptional conditions for analysing slope stability in volcanic rocks because of its mountainous orography with very steep slopes and a wide variety of materials. These conditions have frequently precipitated slope instability, causing significant damage to housing, beaches, roads and other infrastructures. After applying these indices to a number of slopes representative of the island’s wide variety of geological, geomorphological and climatic conditions, the results obtained were compared with the actual behaviour of the slopes, determined from extensive rockfall inventory data and in situ geomechanical surveys.
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D'Amato, J., D. Hantz, A. Guerin, M. Jaboyedoff, L. Baillet, and A. Mariscal. "Influence of meteorological factors on rockfall occurrence in a middle mountain limestone cliff." Natural Hazards and Earth System Sciences Discussions 3, no. 12 (December 21, 2015): 7587–630. http://dx.doi.org/10.5194/nhessd-3-7587-2015.
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Abstract. The influence of meteorological conditions on rockfall occurrence has been often highlighted, but its knowledge is still not sufficient due to the lack of exhaustive and precise rockfall data bases. In this study, rockfalls have been detected in a limestone cliff by annual terrestrial laser scanning, and dated by photographic survey during 2.5 years. A near-continuous survey (1 photo each 10 mn) with a wide-angle lens have allowed dating 214 rockfalls larger than 0.1 m3, and a monthly survey with a telephoto lens, dating 854 rockfalls larger than 0.01 m3. The analysis of the two data bases shows that the rockfall frequency can be multiplied by a factor as high as 7 during freeze–thaw episodes and 26 when the mean rainfall intensity (since the beginning of the rainfall episode) is higher than 5 mm h−1. Based on these results, a 4-level scale has been proposed for predicting the temporal variations of hazard. The more precise data base and freeze–thaw episode definition make it possible to distinguish different phases in freeze–thaw episodes: negative temperature cooling periods, negative temperature warming periods and thawing periods. It appears that rockfalls occur more frequently during warming and thawing periods than during cooling periods. It can be inferred that rockfalls are caused by thermal ice dilatation rather than by dilatation due to the phase transition. But they may occur only when the ice melt, because the cohesion of the ice–rock interface can be sufficient to hold the rock compartment which has been cut.
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Collins, Brian D., Skye C. Corbett, Elizabeth J. Horton, and Alan J. Gallegos. "Rockfall Kinematics from Massive Rock Cliffs: Outlier Boulders and Flyrock from Whitney Portal, California, Rockfalls." Environmental and Engineering Geoscience 28, no. 1 (February 1, 2022): 3–24. http://dx.doi.org/10.2113/eeg-d-21-00023.
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ABSTRACT Geologic conditions and topographic setting are among the most critical factors for assessing rockfall hazards. However, other subtle features of rockfall motion may also govern the runout of rockfall debris, particularly for those sourced from massive cliffs where debris can have substantial momentum during transport. Rocks may undergo collisions with trees and talus boulders, with the latter potentially generating flyrock—launched rock pieces resulting from boulder collisions that follow distinctively different paths than the majority of debris. Collectively, these intricacies of rockfall kinematics may substantially govern the hazards expected from rockfall to both persons and infrastructure located beneath steep cliffs. Here, we investigate the kinematics, including outlier boulder and flyrock trajectories, of seismically triggered rockfalls on 24 June 2020 that damaged campground facilities near Whitney Portal, CA, a heavily used outdoor recreation gateway to the Sierra Nevada mountains. Our results, obtained in part by rockfall runout model simulations, indicate that outlier boulder trajectories resulted from opportunities provided by less steep terrain beyond the talus edge. The influence of trees, initially thought to have served a protective capacity in attenuating rockfall energy, appears to have been negligible for the large boulder volumes (>50 m3) mobilized, although they did potentially deflect the trajectory of flyrock debris. Rockfall outlier boulders from the event were comparable in volume and runout distance to prehistoric boulders located beyond the talus slope, thereby providing some level of confidence in the use of a single rockfall shadow angle for estimating future rockfall hazards at the site.
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Mueller, S. B., N. R. Varley, U. Kueppers, P. Lesage, G. Á. Reyes Davila, and D. B. Dingwell. "Quantification of magma ascent rate through rockfall monitoring at the growing/collapsing lava dome of Volcán de Colima, Mexico." Solid Earth 4, no. 2 (July 11, 2013): 201–13. http://dx.doi.org/10.5194/se-4-201-2013.
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Abstract. The most recent eruptive phase of Volcán de Colima, Mexico, started in 1998 and was characterized by dome growth with a variable effusion rate, interrupted intermittently by explosive eruptions. Between November 2009 and June 2011, activity at the dome was mostly limited to a lobe on the western side where it had previously started overflowing the crater rim, leading to the generation of rockfall events. As a consequence of this, no significant increase in dome volume was perceivable and the rate of magma ascent, a crucial parameter for volcano monitoring and hazard assessment could no longer be quantified via measurements of the dome's dimensions. Here, we present alternative approaches to quantify the magma ascent rate. We estimate the volume of individual rockfalls through the detailed analysis of sets of photographs (before and after individual rockfall events). The relationship between volume and infrared images of the freshly exposed dome surface and the seismic signals related to the rockfall events were then investigated. Larger rockfall events exhibited a correlation between its previously estimated volume and the surface temperature of the freshly exposed dome surface, as well as the mean temperature of rockfall mass distributed over the slope. We showed that for larger events, the volume of the rockfall correlates with the maximum temperature of the newly exposed lava dome as well as a proxy for seismic energy. It was therefore possible to calibrate the seismic signals using the volumes estimated from photographs and the count of rockfalls over a certain period was used to estimate the magma extrusion flux for the period investigated. Over the course of the measurement period, significant changes were observed in number of rockfalls, rockfall volume and hence averaged extrusion rate. The extrusion rate was not constant: it increased from 0.008 ± 0.003 to 0.02 ± 0.007 m3 s−1 during 2010 and dropped down to 0.008 ± 0.003 m3 s−1 again in March 2011. In June 2011, magma extrusion had come to a halt. The methodology presented represents a reliable tool to constrain the growth rate of domes that are repeatedly affected by partial collapses. There is a good correlation between thermal and seismic energies and rockfall volume. Thus it is possible to calibrate the seismic records associated with the rockfalls (a continuous monitoring tool) to improve volcano monitoring at volcanoes with active dome growth.
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Westoby, Matthew, Michael Lim, Michelle Hogg, Lesley Dunlop, Matthew Pound, Mateusz Strzelecki, and John Woodward. "Decoding Complex Erosion Responses for the Mitigation of Coastal Rockfall Hazards Using Repeat Terrestrial LiDAR." Remote Sensing 12, no. 16 (August 13, 2020): 2620. http://dx.doi.org/10.3390/rs12162620.
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A key factor limiting our understanding of rock slope behavior and associated geohazards is the interaction between internal and external system controls on the nature, rates, and timing of rockfall activity. We use high-resolution, monthly terrestrial light detection and ranging (LiDAR) surveys over a 2 year monitoring period to quantify rockfall patterns across a 0.6 km-long (15.3 × 103 m2) section of a limestone rock cliff on the northeast coast of England, where uncertainty in rates of change threaten the effective planning and operational management of a key coastal cliff top road. Internal system controls, such as cliff material characteristics and foreshore geometry, dictate rockfall characteristics and background patterns of activity and demonstrate that layer-specific analyses of rockfall inventories and sequencing patterns are essential to better understand the timing and nature of rockfall risks. The influence of external environmental controls, notably storm activity, is also evaluated, and increased storminess corresponds to detectable rises in both total and mean rockfall volume and the volumetric contribution of large (>10 m3) rockfalls at the cliff top during these periods. Transient convergence of the cumulative magnitude–frequency power law scaling exponent (ɑ) during high magnitude events signals a uniform erosion response across the wider cliff system that applies to all lithologies. The tracking of rockfall distribution metrics from repeat terrestrial LiDAR in this way demonstrably improves the ability to identify, monitor, and forecast short-term variations in rockfall hazards, and, as such, provides a powerful new approach for mitigating the threats and impacts of coastal erosion.
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Dietze, Michael, Solmaz Mohadjer, Jens M. Turowski, Todd A. Ehlers, and Niels Hovius. "Seismic monitoring of small alpine rockfalls – validity, precision and limitations." Earth Surface Dynamics 5, no. 4 (October 16, 2017): 653–68. http://dx.doi.org/10.5194/esurf-5-653-2017.
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Abstract. Rockfall in deglaciated mountain valleys is perhaps the most important post-glacial geomorphic process for determining the rates and patterns of valley wall erosion. Furthermore, rockfall poses a significant hazard to inhabitants and motivates monitoring efforts in populated areas. Traditional rockfall detection methods, such as aerial photography and terrestrial laser scanning (TLS) data evaluation, provide constraints on the location and released volume of rock but have limitations due to significant time lags or integration times between surveys, and deliver limited information on rockfall triggering mechanisms and the dynamics of individual events. Environmental seismology, the study of seismic signals emitted by processes at the Earth's surface, provides a complementary solution to these shortcomings. However, this approach is predominantly limited by the strength of the signals emitted by a source and their transformation and attenuation towards receivers. To test the ability of seismic methods to identify and locate small rockfalls, and to characterise their dynamics, we surveyed a 2.16 km2 large, near-vertical cliff section of the Lauterbrunnen Valley in the Swiss Alps with a TLS device and six broadband seismometers. During 37 days in autumn 2014, 10 TLS-detected rockfalls with volumes ranging from 0.053 ± 0.004 to 2.338 ± 0.085 m3 were independently detected and located by the seismic approach, with a deviation of 81−29+59 m (about 7 % of the average inter-station distance of the seismometer network). Further potential rockfalls were detected outside the TLS-surveyed cliff area. The onset of individual events can be determined within a few milliseconds, and their dynamics can be resolved into distinct phases, such as detachment, free fall, intermittent impact, fragmentation, arrival at the talus slope and subsequent slope activity. The small rockfall volumes in this area require significant supervision during data processing: 2175 initially picked potential events reduced to 511 potential events after applying automatic rejection criteria. The 511 events needed to be inspected manually to reveal 19 short earthquakes and 37 potential rockfalls, including the 10 TLS-detected events. Rockfall volume does not show a relationship with released seismic energy or peak amplitude at this spatial scale due to the dominance of other, process-inherent factors, such as fall height, degree of fragmentation, and subsequent talus slope activity. The combination of TLS and environmental seismology provides, despite the significant amount of manual data processing, a detailed validation of seismic detection of small volume rockfalls, and revealed unprecedented temporal, spatial and geometric details about rockfalls in steep mountainous terrain.
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Zhang, Jie, Zheng Liang, and Chuanjun Han. "Numerical Simulation of Pipeline Deformation Caused by Rockfall Impact." Scientific World Journal 2014 (2014): 1–10. http://dx.doi.org/10.1155/2014/161898.
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Rockfall impact is one of the fatal hazards in pipeline transportation of oil and gas. The deformation of oil and gas pipeline caused by rockfall impact was investigated using the finite element method in this paper. Pipeline deformations under radial impact, longitudinal inclined impact, transverse inclined impact, and lateral eccentric impact of spherical and cube rockfalls were discussed, respectively. The effects of impact angle and eccentricity on the plastic strain of pipeline were analyzed. The results show that the crater depth on pipeline caused by spherical rockfall impact is deeper than by cube rockfall impact with the same volume. In the inclined impact condition, the maximum plastic strain of crater caused by spherical rockfall impact appears when incidence angleαis45°. The pipeline is prone to rupture under the cube rockfall impact whenαis small. The plastic strain distribution of impact crater is more uneven with the increasing of impact angle. In the eccentric impact condition, plastic strain zone of pipeline decreases with the increasing of eccentricityk.
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Liverman, David, Martin Batterson, David Taylor, and Janice Ryan. "Geological hazards and disasters in Newfoundland and Labrador." Canadian Geotechnical Journal 38, no. 5 (October 1, 2001): 936–56. http://dx.doi.org/10.1139/t01-022.
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A geological disaster occurs when natural geological processes impact on our activities, either through loss of life or injury or through economic loss. A geological hazard is a potential disaster. Geological hazard in the Province of Newfoundland and Labrador was studied by archival research using a variety of sources to document the historical record of disaster. This record, although undoubtedly incomplete and selective, demonstrates that the province was affected by numerous geological disasters that inflicted a major economic and social cost. At least 80 people have been killed in Newfoundland and Labrador since 1863 in such incidents, including debris flows, rockfalls, avalanches, and tsunamis. Many Newfoundland communities have developed at the base of steep slopes and are therefore prone to landslides and avalanches or are built adjacent to the coast and are susceptible to storm damage. The economic cost is difficult to estimate, but remedial measures for individual events range from Can$ 20 000 for the construction of 50 m of gabions and retaining walls to Can$ 3 000 000 for community-level coastal flood-protection measures. Many of the documented geological disasters were unavoidable and were the inevitable result of geography. However, some were predictable and therefore preventable, either because a similar event had previously occurred in the same area or because geological factors, such as rapid coastal erosion or rising relative sea levels, were not considered during the planning process. The identification of serious avalanche and rockfall hazards in the Battery, St. John's, has led to installation of protective measures. Archival research methods provide a cheap, effective, and useful means of defining regional geological hazard. Key words: avalanche, landslide, rockfall, hazard, tsunami.
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Zhan, Jiewei, Zhaoyue Yu, Yan Lv, Jianbing Peng, Shengyuan Song, and Zhaowei Yao. "Rockfall Hazard Assessment in the Taihang Grand Canyon Scenic Area Integrating Regional-Scale Identification of Potential Rockfall Sources." Remote Sensing 14, no. 13 (June 23, 2022): 3021. http://dx.doi.org/10.3390/rs14133021.
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Frequent rockfall events pose a major threat to the safe operation of the Taihang Grand Canyon Scenic Area (GCSA) in China. The traditional techniques for identifying potential rockfall sources and hazard assessment methods are often challenged in the alpine canyon landform. This study aims to establish an early identification framework for regional potential rockfall sources applicable to the canyon region and to assess rockfall hazards in potentially hazardous areas using unmanned aerial vehicle (UAV) photogrammetry. Specifically, by incorporating high-precision topographic information and geotechnical properties, the slope angle distribution method was used for static identification of potential rockfall sources. Moreover, SBAS-InSAR technology was used to describe the activity of potential rockfall sources. Finally, taking the key potentially hazardous area of the Sky City scenic spot as an example, the Rockfall Analyst tool was used to analyze the rockfall frequency, bounce height and energy characteristics based on the high-precision UAV 3D real scene model, and the analytic hierarchy process was introduced to achieve quantitative rockfall hazard assessment. The results show that the potential rockfall source areas in the Taihang GCSA is 33.47 km2 (21.47%), mainly distributed in strips on the cliffs on both sides of the canyon, of which the active rockfall source area is 2.96 km2 (8.84%). Taking the scenic spot of Sky City as example, the proposed UAV-based real scene modeling technology was proven to be able to quickly and accurately construct a 3D high-precision model of the canyon area. Moreover, the 3D rockfall simulation showed that the high-energy rockfall area was mainly distributed at the foot of the steep cliff, which mainly threatens the tourist distribution center below. The early identification and quantitative evaluation scheme of rockfall events proposed in this study can provide technical reference for the prevention and control of rockfall hazards in similar alpine valley areas.
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Kromer, Ryan, Matt Lato, D. Jean Hutchinson, Dave Gauthier, and Tom Edwards. "Managing rockfall risk through baseline monitoring of precursors using a terrestrial laser scanner." Canadian Geotechnical Journal 54, no. 7 (July 2017): 953–67. http://dx.doi.org/10.1139/cgj-2016-0178.
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Rockfalls represent significant risks to safe and efficient use of transportation corridors. In this paper, we address the management of rockfall risk through baseline remote monitoring of susceptible slopes (every 2–4 months) along a transportation corridor along the Fraser River valley in western Canada using a terrestrial laser scanner and supporting remote sensing technologies. This includes identifying potential rockfall source zones based on incipient signs of failure, tracking kinematics in three dimensions to better understand the mechanism of failure, estimating potential failure volumes based on bounding joint structure, and transmitting this information to the railway operator for an assessment of risk. We demonstrate our approach for one case along the line where we identified several potential failures ranging in volume from 48 to 4200 m3. Our projections of the location of failures were successful, in that volume projections were within 10%–55%, and the anticipated kinematics and failure mechanism were consistent with the assessment of post-failure rockfall scar geometries. Accurate volume and kinematics estimates are important for the assessment of hazard and risk as well as the planning of risk mitigation options. In general, this approach can be used to better manage risk from rockfall hazard in communities, transportation corridors, or other infrastructure.
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Liu, Haiyang, Xueliang Wang, Xiaohui Liao, Juanjuan Sun, and Su Zhang. "Rockfall Investigation and Hazard Assessment from Nang County to Jiacha County in Tibet." Applied Sciences 10, no. 1 (December 28, 2019): 247. http://dx.doi.org/10.3390/app10010247.
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The influences of rockfall on human engineering have been increasing in Tibet with the rapid development of the western region of China. This study proposed a multi-approach to carry out rockfall investigation and hazard assessment. As a case study, the rockfall hazard from Nang County to Jiacha County in Tibet was assessed. Firstly, we summarized the characteristics of spatial distributions of typical rockfall sources using Digital Elevation Model (DEM) and unmanned aerial vehicle (UAV) aerial images with resolution of 10 m. According to the thresholds of slope angle, slope aspect and elevation distribution of typical rockfall sources, we obtained all of the rockfall source areas in study area semi-automatically in ArcGIS platform. Secondly, we improved the efficiency and accuracy of detailed field investigation by using a three-dimensional (3D) point cloud model and rock mass structure extraction software. According to the analysis result, the dominant joint set was J1, whose orientation was basically consistent with the Yarlung Tsangpo Fault. The combination of J1, J2 and J4 cut the rock mass into blocks of wedge with J1 as potential sliding planes. It was indicated that the stability of the rock mass in study area was mainly controlled by the characters of joint sets. Finally, we applied the improved reclassification criteria of the Rockfall Hazard Vector (RHV) method in rockfall hazard assessment according to protection capabilities of the current protection facilities, making the result more valuable for geohazards prevention work. Based on this multi-approach, we obtained that 10.92% of the 306 provincial highway and 9.38% of the power line were threatened by potential rockfall hazards in study area. The hazard assessment results of study area were also of certain guiding value to the linear project planning and geohazards prevention work.
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Mainieri, Robin, Jérôme Lopez-Saez, Christophe Corona, Markus Stoffel, Eric Mermin, Franck Bourrier, and Nicolas Eckert. "L'inventaire forestier comme méthode de caractérisation spatiale de l'aléa chute de pierres." Schweizerische Zeitschrift fur Forstwesen 170, no. 2 (March 1, 2019): 78–85. http://dx.doi.org/10.3188/szf.2019.0078.
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The contribution of tree inventories to the spatial characterisation of the rockfall hazard Rockfall is one of the most frequent natural hazards in mountain areas. The characterisation of rockfall activity in terms of frequency, intensity (energy) and dispersion (run-out distance) is essential for risk management, but is extremely complex due to the diffuse nature of this hazard and the gaps in historical records. In this study we show that trees can be reliable bioindicators to reconstruct rockfall activity. Our method is based on the combination of a systematic mapping of all trees (location, breast height diameter, species) and the complete recording of all visible scars. On an area of one hectare in the municipality of Saint-Guillaume (Vercors massif, French Alps) we recorded 793 trees and 2333 scars. The spatial distribution of the tree species and scars was used to locate the most active source areas and the most important rockfall trajectories and to show the decreasing rockfall activity with increasing distance to the source area and thus also the protective effect of the forest. The approach is particularly valuable in areas where historical records are lacking. It can be used in the future to 1) refine hazard zoning and 2) calibrate rockfall models. Thanks to the recorded tree data, the area could also be used as a marteloscope for practicing silvicultural interventions in the rockfall protection forest.
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Jacklitch, Carl, Abdul Shakoor, and William R. Lund. "Evaluation of Rockfall-hazard Potential For Rockville, Utah, Following a 2013 Fatal Rockfall." Environmental and Engineering Geoscience 24, no. 2 (May 23, 2018): 143–63. http://dx.doi.org/10.2113/eeg-2041.
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Abstract In December 2013, a rockfall in the town of Rockville, Utah, released an estimated 2,700 tons (2,450 tonnes) of rock from a 400-ft (122-m) high slope; the rock struck a house at the base of the slope, resulting in two fatalities. We performed detailed field and laboratory investigations to (1) identify the modes of failure and factors contributing to rockfalls along the east-west trending, south-facing slope where it passes through the town; (2) identify sections of the slope that pose the highest hazard for future property damage or injury; and (3) suggest potential remedial measures. Field investigations included mapping discontinuities, establishing stratigraphy, measuring slope geometry, and evaluating potential failure modes at four selected sites. Laboratory investigations included determining dry density, friction angle, and slake durability index of rock samples. Using the Dips software, we determined the principal joint sets and performed a kinematic analysis. The maximum rollout distances for rock blocks of various sizes were determined for each of the study sites using the RocFall software. Results of the kinematic analysis and field observations indicate that wedge, plane, and toppling failures are possible within the Shinarump Conglomerate Member of the Chinle Formation and the Upper Red Member of the Moenkopi Formation along the entire slope. Based on the results of the study, we developed a rockfall-hazard map that indicates that the western portion of the town faces the highest hazard from potential rockfalls. The most feasible future remedial measure is not to build close to the hazardous slopes. Other possible remedial measures include removing loose rock blocks, installing rock anchors, and using drapery mesh.